Engine speed governors are commonly used on internal combustion engines in many different applications. Typical applications are for vehicle engines of trucks and buses. As is well known, speed governors are employed for the purposes of limiting operating speeds and for protecting the engines from damage due to overspeeding.
Combined engine and load speed governors have been developed which are responsive to both engine speed and vehicle speed for controlling or limiting the engine speed. A governor of this type is disclosed in U.S. patent application Ser. No. 794,615 filed by Harry D. Sturdy on May 6, 1977 now U.S. Pat. No. 4,181,103. An electronic control circuit especially adapted for a governor of the type disclosed in said patent application is disclosed and claimed in my U.S. Pat. No. 4,090,480 granted May 23, 1978.
An improved engine and load speed governor has been developed which allows the engine to be accelerated to its predetermined speed limit with small overshoot beyond that limit and which quickly regulates the engine speed close to the predetermined limit with only small deviation. Such action is obtained by positioning the engine throttle to a predetermined reference position upon acceleration of the engine to the predetermined speed and actuation of the engine governor thereby, rather than by driving the throttle toward the fully closed position. The governor functions to safely control engine and load without dynamic surging when operating the engine speed control mode. Additionally, the governor includes an overspeed control which acts to close the throttle beyond the reference position toward the completely closed throttle position in the event of a persistent overspeed. This improved engine and load speed governor is disclosed and claimed in a U.S. patent application filed by Harry D. Sturdy on or about May 12, 1979 entitled "Engine Governor With Reference Position For Throttle Limiter". A governor of this type is made and sold by Sturdy Truck Equipment, Inc. of Wilmington, North Carolina.
The electronic control circuit of this invention is especially adapted for use with the aforementioned improved engine and speed governor.